This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. There are many human diseases, such as Malaria or Chagas Disease, which are caused by eukaryotic microbes. Treatment of these diseases is often difficult, because the causative organisms do not respond to antifungal or antibiotic treatment. Pythiosis is an emerging disease caused by the oomycete, Pythim insidiosum, for which the only current treatment is large-scale removal of infected tissue. We propose to use a comparative genomics approach to identify gene families that have expanded in pathogenic oomycetes, relative to their oomycetes that are either facultative pathogens or free living decomposers. To accomplish this, we will sequence a draft genome of the free living oomycete, Thraustotheca clavatum and use these data in combination with other oomycete genomes in a 'gene networks'analysis. The approach will rapidly highlight gene families that expand in response to a parasitic life style. Expanded gene families common to multiple pathogens will be investigated as possible drug targets to combat oomycete infections.